Abstract: The present invention is concerned with compounds of formula I ##STR1## wherein A, B, M, R, Ar and Het are as defined in the specification, pharmaceutically acceptable ester and amide derivatives thereof; N-oxides thereof, tetrazole derivatives thereof, and salts thereof. These compounds have valuable pharmacological activities, especially as inhibitors of thromboxane synthetase and as receptor antagonists of thromboxane A.sub.2 and prostaglandin H.sub.2.

Abstract: Disclosed are the compounds of formula ##STR1## wherein A represents lower alkylene; B represents oxygen, sulfur, lower alkylene, lower alkylene interrupted by oxygen, sulfur, sulfinyl or sulfonyl, (oxy-, sulfinyl-, sulfonyl- or thio)-lower alkylene, lower alkenylene, phenylene or a direct bond; M represents lower alkylene, lower alkylene interrupted by oxygen, sulfur, sulfinyl or sulfonyl, (oxy-, sulfinyl, sulfonyl- or thio)-lower alkylene, lower alkenylene or a direct bond; or one of A, B and M represents lower alkylidenylene and the other two independently represent lower alkylene; R represents hydrogen unless A, B or M represents lower alkylidenylene in which case R represents the second bond to the adjacent aklylidenylene unsaturated carbon atom; Het represents 1-imidazolyl, 3-pyridyl, or 1-imidazolyl or 3-pyridyl substituted by lower alkyl; Ar represents carbocyclic or heterocyclic aryl; pharmaceutically acceptable ester and amide derivatives thereof; the N-oxides of said compounds wherein Het represent